This invention relates to a process for producing 1,1,1-trichloroethane by reacting 1,1-dichloroethane with chlorine.
1,1,1-Trichloroethane is commonly produced by the hydrochlorination of vinylidene chloride or the chlorination of 1,1-dichloroethane. The latter has been done by either thermal chlorination or photochlorination. The photochlorination is presently done by irradiating mixtures of 1,1-dichloroethane and chlorine with broad spectrum lamps.
The major problem in such chlorination reactions is the production of by-products, mainly 1,1,2-trichloroethane. Other by-products produced include 1,1,2,2-tetrachloroethane, 1,1,1,2-tetrachloroethane and 1,1,1,2,2-pentachloroethane. In the conventional chlorination reactions, in excess of 30 percent of the 1,1-dichloroethane chlorinated forms these by-products. Mintz, U.S. Pat. No. 3,580,831, teaches that catalytic amounts of iodine improve the selectivity of photochlorination of mono- and 1,1-dichloroethane with actinic light.
In Okado et al., Japanese Pat. No. 55-079,329 (1980), the use of iodine and iodine compounds to improve the selectivity of chlorination of 1,1-dichloroethane is taught. It is further taught that the use of iodine or iodine compounds in liquid phase photochlorination results in especially good selectivity.
Okado et al., German Pat. No. 3,011,689, teaches the use of iodine and iodine compounds as catalysts in vapor phase photochlorination of 1,1-dichloroethane and that these catalysts improve selectivity.
Rideout et al., U.S. Pat. No. 4,301,314, teaches that the addition of between 100 and 600 parts per million of oxygen during the thermal chlorination of 1,1-dichloroethane improves the selectivity of that reaction for 1,1,1-trichloroethane. Rideout et al., U.S. Pat. No. 4,192,823, teaches that the addition of between about 500 to 100,000 parts per million of carbon dioxide during the thermal chlorination of 1,1-dichloroethane improves the selectivity of that reaction for 1,1,1-trichloroethane.